A byproduct of many human activities is the generation of solid waste. In many industrial, commercial and large scale residential facilities, this waste is placed in large containers that have capacities of at least 30 yd.sup.3. Once one of these containers is filled, a hauler transports the container to a landfill or other disposal site. Typically, when a hauler goes to site, it brings a new, empty waste container to replace the filled container.
At many facilities at which a waste container is located, a compacting unit is employed to compress the waste that fills the container. Clearly, compacting the waste reduces the frequency with which the container needs to be emptied. Also, at many landfills and other disposal sites, the charges to empty a container are a function of container volume. It is in the best interests of the hauler unloading the container to have as much waste as possible packed into the container before it is transported to these sites for emptying. Most compacting units include some type of ram that, when actuated, projects into the container to compress the waste. Most rams are hydraulically actuated. Some compactors have rams that are automatically controlled. These compactors are designed so that the time period for which the ram is allowed to extend is preset. Other compactors have manually controllable rams. These compactors allow the individual using the compactor to control the time the ram is allowed to extend each time the ram is extended.
It is often the responsibility of the hauler to remove and replace a filled waste container without any prompting from the business at which the container is located. At these facilities, the containers are typically picked up on a scheduled basis. At other facilities, the hauler removes the filled container on a "will call" basis. At these facilities, the facility operators usually prompt the hauler in order to have the filled containers removed. As discussed above, the economics of waste transport and processing dictate that a container should not be removed from a facility until it is substantially full. Accordingly, a number of systems have recently been developed that provide indications of the fill state of a waste container. Some of these systems operate by monitoring the pressure of the hydraulic fluid that actuates the ram which compresses the waste. These systems generate an indicia of container fullness based on the principle that, as the container is filled, the pressure of this fluid increases in order to provide the force needed to compress the waste. Other systems monitor the number of times the compacting ram is actuated after an empty container is placed at a facility. These systems provide an indication of container fullness based on the assumption that container fullness is directly related to ram use. Some systems monitor first one and then a second one of the above parameters to provide different indica of the container fullness.
Regardless of the actual algorithm employed to determine container fullness, most monitoring systems have some type of data transmission components. These transmission components transmit the data from the waste container to a central location, typically the hauler's dispatcher's office. This data can be the raw data generated by transducers integral with the compactor and/or processed data including the indication of container fullness. The dispatcher evaluates this data to determine the fullness of the individual containers. Based on these evaluations, the dispatcher schedules the pick-up and replacement of the individual containers.
While current systems for determining container fullness offer some indication of container fullness, it has been found that the data they generate is sometimes lacking in precision. This is because variations in each actuation of a compactor can significantly skew the resultant determination of container fullness. These variations occur because, at most facilities, different people tend to the loading of the container and control the actuation of the compactor. Accordingly, if one person, whether out of caution or boredom, frequently actuates the compactor, a use-based determination of container fullness may indicate a container is substantially full when, in fact, that is not the case. At another facility, an individual with responsibility for filing a compactor may actuate the compactor at less frequent basis than his/her coworkers. If the compactor is provided with a pressure-based system for evaluating container fullness, the data generated during this individual's uses can likewise produce an indication of fullness that is incorrect. Also, with a manually operated compactor, the time periods the ram is actuated may significantly vary depending with the individuals tending the container. These variations can adversely effect the accuracy of both use-based and pressure-based calculations of container fullness.
There have been some attempts to compensate for these individual variations in compactor use. For example, some systems are designed to provide an indication of compactor fullness based on average pressure or discard some high pressure readings. While these systems may offer some improved accuracy, they still can generate inaccurate indications of container fullness in some situations.
Moreover, many waste haulers would like to know more than the extent to which their containers are full. It is very helpful if a hauler can be provided with an indication of when, at a time in the future, a particularly container is expected to be completely full. If a waste hauler has this forecast, it can then schedule the pick-up and replacement of the container to occur at a time just before the container is full. Such scheduling accomplishes two goals. First, this scheduling minimizes the pick-up costs since the number of times the container is picked up and emptied is kept to a minimum. Secondly this scheduled reduces, if not eliminates the situation arising in which the container is completely filled and the waste-generator must find another, temporary location for the waste until the new container is delivered.
A system for forecasting when a waste container will be full is disclosed in PCT Publication No. WO 97/40 975, based on PCT Application No. PCT/US97/06779, filed April 29, 1997, which is incorporated herein by reference. The system disclosed in this document generates a database of the number of times per time period, (day-of-week, shift-of-work) a compactor is employed to compress the waste in a container. The system also generates an indication of number of remaining times a compactor can be employed to compress the waste in a container. Once the system calculates this intermediate data, it generates a forecast of the time period in future during which the container will be full. While this system has been used with some success, this success has been limited. This is because, for the reasons discussed above, it has been difficult to provide an accurate indication of container fullness. Consequently, it has been equally difficult to provide an accurate forecast of the number of times the compactor can be used in the future before the container will be filled. Since this latter variable has proven difficult to accurately generate, the ability to predict when, in the future, a container will be full has similarly proved difficult to accurately forecast.